Consumer grade messaging gained mass acceptance with the advent of SMS text messages on cell phones. SMS messages are limited to 140 characters and sent from one person to another person. Later advancements allowed people to send SMS messages to a group of recipients. Technological innovations such as social networks have allowed people to join groups, to follow certain personalities, and to subscribe to pages. The social networks are, in general, refinements of internet newsgroups and RSS (really simple syndication) readers.
Cell phones, smart phones in particular, provide individual people with small and surprisingly powerful portable computers. Most smart phones are also perpetually connected to at least one data network and are location aware. They know where they are and can report their locations. Furthermore, smart phones can run ‘apps’. Most apps are simple computer programs that make use of the phone's hardware and services provided by the phone's operating system.
Location aware apps are available for smart phones. These apps include mapping and travel routing applications. Other available applications allow people to interact with each other based on proximity.
FIG. 1, labeled as ‘prior art’, illustrates proximity based interaction. A person 102 with a GPS (global positioning system) enabled cell phone can interact with a second person 104 within a certain radius 106. The radius 106 defines an area 101 bounded by a circle 105. A third person 103 outside the circle 105 is outside the area of interaction. The proximity based scheme has proven very effective in helping people find nearby goods, services, friends, and dates. Greater services are needed and they can be provided by systems and methods having capabilities above and beyond those based only on proximity to a sender.